Hermetic silicon carbide

ABSTRACT

Hermetic amorphous doped silicon carbide is deposited on an integrated circuit substrate in a PECVD reactor. Nitrogen-doping of an SiC film is conducted by flowing nitrogen-containing molecules, preferably nitrogen or ammonia gas, into the reactor chamber together with an organosilane, preferably tetramethylsilane, and forming a plasma. Oxygen-doping is conducted by flowing oxygen-containing molecules into the reaction chamber.

RELATED APPLICATIONS

[0001] This application is a continuation-in-part application ofcommonly-owned and copending U.S. patent application Ser. No.10/099,232, filed Mar. 13, 2002.

FIELD OF THE INVENTION

[0002] The invention is related to the field of hermetic barrier layersin integrated circuits, in particular, silicon carbide barrier layers.

BACKGROUND OF THE INVENTION

[0003] Statement of the Problem

[0004] There is a need in integrated circuits for hermetic barrierlayers having low dielectric constants. When silicon carbide, SiC, isused as a barrier to protect underlying films in integrated circuitdevices, moisture penetration through the silicon carbide needs to beminimized. SiC films prepared by conventional PECVD methods show anabundance of Si—H and Si—(CH₃)_(x) in the films, leading to moisturepermeability of the SiC films. The problem is attributable mainly to thelow film density caused by bulky —(CH₃) groups, which generate largefree volume inside the films and lead to ambient moisture penetration.Attempts in the prior art to increase hermeticity of barrier films oftenresult in films having high dielectric constants, for example, of about6.

SUMMARY OF THE INVENTION

[0005] The invention helps to solve some of the problems mentioned aboveby providing methods for fabricating a silicon carbide layer on anintegrated circuit having good moisture-barrier properties and a lowdielectric constant. A silicon carbide layer fabricated in accordancewith the invention typically has a dielectric constant in a range ofabout from 4 to 5.

[0006] In one basic embodiment, the invention provides a plasma-enhancedmethod for depositing nitrogen-doped silicon carbide on an integratedcircuit substrate. In one aspect, a method comprises flowing gaseousorganosilane molecules into a reaction chamber. In another aspect,gaseous nitrogen-containing doping molecules are flowed into thereaction chamber. In another aspect, a gas plasma is formed in thereaction chamber. Preferably, the organosilane molecules comprisemolecules having no Si—H bonds. Most preferably, the organosilanemolecules comprise tetramethyl silane.

[0007] In another aspect, the doping molecules are selected from thegroup consisting of nitrogen gas, N₂, and ammonia gas, NH₃. Preferably,the flowrate of doping molecules into the reaction chamber is more thanfour times greater than the organosilane flowrate. In another aspect, amethod in accordance with the invention comprises applying alow-frequency radio-frequency (“rf”) bias to the substrate. In stillanother aspect, the applied bias has a frequency in a range of aboutfrom 100 kHz to 600 kHz. In another aspect, a method comprises a step ofthe applying a low-frequency rf bias to the substrate at a power in arange of about from 200 to 2000 Watts. Preferably, the low-frequency rfbias has a frequency of about 250 kHz and is applied in a range of aboutfrom 300 to 600 Watts.

[0008] In another aspect, forming a gas plasma comprises applyinghigh-frequency radio frequency power to the reaction chamber. In stillanother aspect, applying high-frequency power comprises applying powerhaving a frequency in a range of about from 10 MHz to 30 MHz, preferablyabout 13.6 MHz. In another aspect, applying high-frequency rf powercomprises applying power in a range of about from 200 to 4000 watts.Preferably, power is applied in a range of about from 300 to 1400 wattsto form a plasma.

[0009] In another aspect, a method in accordance with the inventioncomprises a step of maintaining the reaction chamber at a pressure in arange of about from 0.8 to 10 Torr. Preferably, the reaction chamber ismaintained at a pressure in a range of about from 3 to 5 Torr. Inanother aspect, a method in accordance with the invention comprises astep of maintaining the reaction chamber at a temperature in a range ofabout from 200° to 600° C. Preferably, the reaction chamber ismaintained at a temperature in a range of about from 350° to 425° C.

[0010] Another basic embodiment of a method in accordance with theinvention provides a plasma-enhanced method for depositing oxygen-dopedsilicon carbide on an integrated circuit substrate. In one aspect, amethod comprises flowing gaseous organosilane molecules into a reactionchamber. In another aspect, gaseous oxygen-containing doping moleculesare flowed into the reaction chamber. In still another aspect, a gasplasma is formed in the reaction chamber. In still another aspect, theorganosilane molecules comprise molecules having no Si—H bonds.Preferably, the organosilane molecules comprise tetramethyl silane.

[0011] In another aspect, the doping molecules comprise a weak oxidizer.In another aspect, the doping molecules comprise carbon dioxide, CO₂. Inanother aspect, weak-oxidizer oxygen doping molecules are flowed intothe reaction chamber at a doping flowrate more than four times greaterthan the organosilane flowrate.

[0012] In another aspect, a method comprises the step of applying alow-frequency rf bias to the substrate, preferably at a frequency in arange of about from 100 kHz to 600 kHz. In another aspect, alow-frequency rf bias is applied to the substrate at a power in a rangeof about from 200 to 2000 Watts. In another aspect, a low-frequency rfbias is applied to the substrate at a frequency of about 250 kHz in arange of about from 400 to 800 Watts.

[0013] In another aspect, applying high-frequency rf power comprisesapplying power in a range of about from 200 to 4000 watts, preferably ina range of about from 300 to 1400 watts. In still another aspect, thereaction chamber is maintained at a pressure in a range of about from0.8 to 10 Torr, preferably at a pressure in a range of about from 1.5 to3 Torr. In another aspect, the reaction chamber is maintained at atemperature in a range of about from 200° to 600° C., preferably in arange of about from 350° to 425° C.

[0014] In still another aspect, a method for depositing oxygen-dopedsilicon carbide comprises flowing oxygen doping molecules comprising astrong oxidizer, such as oxygen gas, (O₂) nitrous oxide (N₂O), and ozone(O₃). In still another aspect, the step of flowing doping molecules intothe reaction chamber comprises flowing oxygen doping molecules at adoping flowrate about the same or less than the organosilane flowrate.

[0015] A third basic embodiment of a method in accordance with theinvention provides a plasma-enhanced method for depositing doped siliconcarbide containing both nitrogen dopant and oxygen dopant. In oneaspect, gaseous organosilane molecules are flowed into a reactionchamber. In another aspect, gaseous nitrogen doping molecules and oxygendoping molecules are flowed into the reaction chamber. In anotheraspect, a gas plasma is formed in the reaction chamber.

[0016] In another aspect, the organosilane molecules comprise moleculeshaving no Si—H bonds. Preferably, the organosilane molecules comprisetetramethyl silane. In another aspect, the nitrogen doping molecules areselected from the group consisting of nitrogen gas, N₂, and ammonia gas,NH₃, and the oxygen doping molecules comprise a weak oxidizer, forexample, carbon dioxide, CO₂. In another aspect, the step of flowing thenitrogen doping molecules and weak-oxidizer oxygen doping molecules intothe reaction chamber comprises flowing the doping molecules at a dopingflowrate more than four times greater than the organosilane flowrate.

[0017] In another aspect, the nitrogen doping molecules are selectedfrom the group consisting of nitrogen gas, N₂, and ammonia gas, NH₃, andthe oxygen doping molecules comprise a strong oxidizer, for example,oxygen gas, (O₂), nitrous oxide (N₂O), and ozone (O₃). In anotheraspect, the step of flowing the nitrogen doping molecules andstrong-oxidizer oxygen doping molecules into the reaction chambercomprises flowing the nitrogen doping molecules at a nitrogen dopingflowrate more than two times greater than the organosilane flowrate, andflowing the strong-oxidizer oxygen doping molecules at an oxygen dopingflowrate about the same or less than the organosilane flowrate.

[0018] In another aspect, a low-frequency rf bias is applied to thesubstrate. In another aspect, the low-frequency rf bias is applied at afrequency in a range of about from 100 kHz to 600 kHz. In still anotheraspect, the low-frequency rf bias is applied at a power level in a rangeof about from 200 to 2000 Watts. In another aspect, the step of applyinga low-frequency rf bias to the substrate comprises applying a bias at afrequency of about 250 kHz in a range of about from 300 to 600 Watts. Inanother aspect, forming a gas plasma comprises applying high-frequencyrf power to the reaction chamber. In another aspect, applyinghigh-frequency rf power comprises applying power having a frequency in arange of about from 10 MHz to 30 MHz, preferably about 13.6 MHz. Inanother aspect, applying high-frequency rf power comprises applyingpower in a range of about from 200 to 4000 watts. In another aspect,applying high-frequency rf power comprises applying power in a range ofabout from 300 to 1400 watts.

[0019] In another aspect, depositing a silicon carbide layer containingboth nitrogen and oxygen dopant comprises maintaining the reactionchamber at a pressure in a range of about from 0.8 to 10 Torr,preferably in a range of about from 2 to 4 Torr. In another aspect, thereaction chamber is maintained at a temperature in a range of about from200° to 600° C., preferably in a range of about from 350° to 425° C.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] A more complete understanding of the invention may be obtained byreference to the drawings, in which:

[0021]FIG. 1 includes a graph in which SiC-film density was plotted as afunction of the measured content of Si—C bonds and Si—N (or Si—O) bondsin SiC films; and

[0022]FIG. 2 includes a graph in which measured content of Si—C bondsand Si—N (or Si—O) bonds in five SiC films was plotted as a function ofthe stress change;

[0023]FIG. 3 shows a graph in which the atomic concentration of silicon,carbon, nitrogen and oxygen atoms in a selected nitrogen-doped SiC filmis plotted as a function of sputter time.

DESCRIPTION OF THE INVENTION

[0024] The invention is described herein with reference to exemplarynitrogen-doped and oxygen-doped silicon carbide films. It should beunderstood that the particular embodiments and serve explanatorypurposes and are not limiting descriptions of structures and methods inaccordance with the invention. Furthermore, exemplary silicon carbidefilms discussed herein below were fabricated in accordance with theinvention in a Novellus “Sequel” PECVD module, which accommodates six200 mm wafers. The flow rates of gaseous streams presented and discussedin the application are total flow rates into a Novellus “Sequel”reactor. It is understood that silicon carbide deposition may also beconducted using an apparatus having a volume and wafer-capacitydifferent from the module used in Example 1 without departing from thescope of the invention. Thus, the embodiments described herein areexemplary and are not intended to limit the scope of the invention,which is defined in the claims below.

[0025] An object of a method in accordance with the invention isfabrication of a hermetic amorphous silicon carbide layer having a lowdielectric constant. A silicon carbide film in accordance with theinvention is particularly useful as a barrier in an integrated circuit:for example, as a barrier layer in a copper damascene structure, as anetch stop, and as an intermetal dielectric layer. Film hermeticity andlow moisture permeability are improved, compared to conventional barrierfilms. It is believed that improved hermeticity and reduced moisturepermeability are achieved through increased film density. A doping ofsilicon carbide with nitrogen or oxygen or both reduces the relativenumbers of Si—H, Si—CH_(x) and similar bonds, which are related to openstructures causing relatively low-density in conventional barrier films.Doping with nitrogen or oxygen or both in accordance with the inventionleads to higher density and lower hydrogen content in the depositedsilicon carbide films.

[0026] In accordance with the invention, organosilane molecules flowinto a reaction chamber, preferably into a PECVD reaction chamber.Preferably, the relative number of Si—H bonds in the organosilane isminimized. For this reason, the organosilane molecules preferablycomprise fully R-substituted silanes and other organosilanes. In theexamples presented below, tetramethyl silane (“4MS)”, Si(CH₃)₄, was usedto deposit silicon carbide films in accordance with the invention.

[0027] Nitrogen-doping and oxygen-doping in accordance with theinvention is conducted by flowing nitrogen-containing doping moleculesor oxygen-containing doping molecules or both into the reaction chamber,in which a plasma is formed by applying energy to the resulting reactionmixture. Nitrogen doping molecules typically comprise nitrogen gas, N₂,or ammonia gas, NH₃, or both. Oxygen doping molecules typically compriseweak-oxidizer oxygen-containing molecules, such as CO₂. In anotherembodiment in accordance with the invention, strong-oxidizer molecules,such as gaseous oxygen (O₂), nitrous oxide (N₂O), and ozone (O₃), areflowed into the reactor. Because the strong-oxidizer oxygen atomspresent in the plasma are so reactive, it is necessary to limit theamount of strong-oxidizer molecules flowing into the reaction chamber toa relatively small amount, for example, about the same or less than thenumber of organosilane molecules. Otherwise, the number of oxygen atomsincorporated into the deposited layer will exceed dopant levels andadversely affect the barrier properties of the silicon carbide.

[0028] High-frequency radio-frequency (“hf-rf”) power, typically in arange of about from 10 MHz to 30 MHz, preferably at 13.6 MHz, is used toform a plasma from the reactant gases in the reaction chamber.Preferably, low-frequency radio-frequency (“lf-rf”) energy, typically atabout 250 kHz, is applied to the substrate to create a bias. Thelow-frequency bias tends to increase hermeticity in a silicon carbidefilm in accordance with the invention.

[0029] A set of representative ranges of operating variables andconditions for depositing hermetic silicon carbide in accordance withthe invention is presented here. The flow rates listed are valid for aNovellus “Sequel” PECVD module treating six integrated circuit wafersubstrates to deposit doped silicon carbide. It is understood that theflow rates listed here would require modification for a different-sizedreaction chamber. Tetramethylsilane flow: 100-2000 sccm CO₂ flow: 0-8000 sccm N₂ flow:  0-5000 sccm NH₃ flow:  0-5000 sccm O₂ flow: 0-400 sccm inert gas flow:  0-3000 sccm (e.g., He) hf-rf: 200-4000 Wlf-rf:  0-2000 W Pressure:  0.8-10 Torr Temperature: 200-600° C.

[0030] As mentioned above, tetramethyl silane, 4MS, is preferred in amethod in accordance with the invention. 4MS is particularly usefulbecause it contains no active H-group, i.e., no S—H bond. An activeH-group encourages cross-linking in silicon carbide. The absence of anactive H-group reduces the amount of free hydrogen in a silicon carbidelayer.

[0031] Pressure in a PECVD reaction chamber used in accordance with theinvention is in a range of about from 0.8 to 10 Torr. When nitrogendoping, the preferred range is about from 3 to 5 Torr. When oxygendoping, the preferred range is about from 1.5 to 3 Torr. When dopingwith both nitrogen and oxygen, the preferred range is about from 2 to 4Torr. Generally, the lower the pressure, the better is the hermeticity.A preferred temperature range is 300-450° C., and a most preferred rangeis about from 350 to 425° C.

[0032] A hermetic silicon carbide film fabricated in accordance with thepresent invention has a dielectric constant in a range of about 4.0-5.0.Useful thicknesses of silicon carbide coatings fabricated in accordancewith the invention are in a range of about from 10 nm to 4 μm. Siliconcarbide coatings used as intermetal dielectric layers and other types ofbarriers in integrated circuits typically have a thickness in a range ofabout from 50 to 80 nm. The deposition rate of silicon carbide in themethod in accordance with the invention is typically in a range of aboutfrom 50 to 300 nm/min, and preferably in a range of about from 100 to150 nm/min. The deposition rate is controlled principally by varying thepressure and temperature of the reaction chamber and the power of thelow-frequency rf bias applied to the substrate.

EXAMPLE 1

[0033] A series of doped silicon carbide films were fabricated undervarious conditions in accordance with the invention using a Novellus“Sequel” PECVD module, which holds six 200 mm wafers. In addition,silicon carbide films without nitrogen or oxygen doping were alsoproduced under similar conditions but without flowing nitrogen doping oroxygen doping molecules into the reaction chamber. The hermeticity ofthe films was then determined. Hermeticity is a measure of themoisture-barrier capability of a deposited film. Hermeticity values arerelative values and were determined using measurements from a tensileTEOS method, in particular, the Pressure Cook method. Each doped SiCfilm of approximately 70-75 nm thickness was deposited on top of a thicktensile TEOS film, the TEOS film typically having a thickness of 500 nmwith stress of 2.4·10⁹ dynes/cm². The SiC/TEOS stack was “cooked” inwater vapor at 120° C. and 2 atm pressure for 10 hours. The stress driftof the film stack was then measured. The measured stress shift gives aquantitative measure of how hermetic the SiC film is. The less stressdrift of a tensile SiC/TEOS stack that occurred, the more hermetic isthe SiC film. The stress shift was then converted and linearized into a“hermeticity” scale, having a value from 0 to 10, with 0 indicating theworst hermeticity, and 10 indicating the best hermeticity. The stressshift of stacks containing a non-doped SiC film showed the most stressshift, corresponding to a hermeticity value of 0. On the other hand, anidealized zero-shift corresponded to a hermeticity value of 10. Theactual calculated values of hermeticity of the SiC films doped inaccordance with the invention were therefore between 0 and 10. Ahermeticity value of 5 or higher may be considered good.

[0034] Table 1 below shows operating conditions used in fabricatingdoped silicon carbide films in accordance with the invention, as well asnon-doped silicon carbide films. Pure gases were flowed into thereaction chamber at the flow rates indicated. The high-frequency was13.56 MHz. The low-frequency value was 250 kHz. The operatingtemperature for all of the examples was about 400° C. Table 1 alsoincludes calculated hermeticity values for each of the SiC films listed.It should be understood that Table 1 does not include all processcombinations tested. It should be likewise understood that manydifferent combinations of process operating conditions not shown inTable 1 may be utilized in accordance with the invention. TABLE 1Hermeticity 4MS CO2 Pressure HF LF (0-worst, (Sccm) (Sccm) N2 NH3 (Torr)(W) (W) 10-best) SiC n1 500 2500 0 0 2 600 400 4 SiC n2 500 2500 0 0 2600 700 6 SiC n3 500 2500 0 0 2 600 550 5 SiC n4 500 2500 0 0 2 800 4003 SiC n5 500 2500 0 0 2 1100 550 5 SiC e6 500 2500 0 0 1.8 600 300 3 SiCn6 700 3500 0 0 2 600 550 5 SiC n7 700 3500 0 0 2 600 400 4 SiC n8 7003500 0 0 2 600 700 6 SiC n9 700 3500 0 0 2 800 400 4 SiC n10 700 3500 00 2 1100 550 5 SiC n11 700 3500 0 0 3 600 600 2 SiC n12 700 3500 0 0 3600 400 1 SiC n13 700 3500 0 0 3 600 800 3 SiC nd1 400 0 2000 750 4.5950 400 5 SiC nd2 400 0 2000 750 4.5 700 400 6 SiC nd3 400 0 2000 7504.5 450 400 6 SiC nd4 400 0 2000 750 4.5 1200 400 6 SiC ne1 400 0 1000750 4 500 500 5 SiC ne2 400 0 2000 750 4 1200 500 8 SiC ne3 400 0 1000750 4 1200 500 4 SiC ne4 400 0 2000 400 4 500 500 8 SiC ne5 400 0 2000750 4 500 500 9 SiC ne6 400 0 1000 400 4 1200 500 2 SiC ne7 400 0 1000400 4 500 500 2 SiC ne8 400 0 2000 400 4 1200 500 7 SiC ns1 350 0 0 40004 500 500 5 SiC ns2 2000 0 0 0 2.3 500 500 0

[0035] A review of the results calculated in Table 1 indicates thatnumerous combinations of variables and operating conditions are usefulto make hermetic silicon carbide in accordance with the invention.

[0036] In the graph of FIG. 1, SiC-film density was plotted as afunction of the measured content of Si—C bonds and Si—N (or Si—O) bondsin representative SiC films. Film density was measured by a RutherfordBack Scattering (“RBS”) technique. Film content was measured using aFourier Transform Infrared (“FTIR”) technique. The triangle-shaped datapoints show that film density increased as the concentration of Si—N (orSi—O) bonds increased. Conversely, the square-shaped data points showthat film density decreased as the concentration of Si—C bondsincreased.

[0037] In the graph of FIG. 2, the measured content of Si—C bonds andSi—N (or Si—O) bonds in five representative SiC films was plotted as afunction of the stress change. Film content was measured using FTIR.Stress change was measured using the tensile TEOS test. Thediamond-shaped data points show that increased stress is related todecreased Si—N content.

[0038] In the graph of FIG. 3, the atomic concentration of silicon(“Si”), carbon (“C”), nitrogen (“N”) and oxygen (“O”) atoms in aselected nitrogen-doped SiC film is plotted as a function of sputtertime during which the deposited film was sputtered away and the atomicconcentration was measured using an XPS technique. The designations “1s”and “2p” are standard electron orbital designations. The examined filmwas deposited in accordance with the invention using the followingoperating conditions: 4MS, 350 sccm; N₂, 1350 sccm; NH₃, 550 sccm; hf-rf500W; lf-rf 500 W; 4 Torr; 400° C. The plotted results show lowpermeation of oxygen into the deposited SiC film, indicating goodhermeticity.

[0039] Methods and barrier films in accordance with the invention areuseful in a wide variety of circumstances and applications to providehermetic silicon carbide having a low dielectric constant. It is evidentthat those skilled in the art may now make numerous uses andmodifications of the specific embodiments described, without departingfrom the inventive concepts. It is also evident that the steps recitedmay, in some instances, be performed in a different order; or equivalentstructures and processes may be substituted for the structures andprocesses described. Since certain changes may be made in the abovesystems and methods without departing from the scope of the invention,it is intended that all subject matter contained in the abovedescription be interpreted as illustrative and not in a limiting sense.Consequently, the invention is to be construed as embracing each andevery novel feature and novel combination of features present in orinherently possessed by the methods and compositions described in theclaims below and by their equivalents.

We claim:
 1. A plasma-enhanced method for depositing nitrogen-dopedsilicon carbide on an integrated circuit substrate, comprising steps of:flowing gaseous organosilane molecules into a reaction chamber at anorganosilane flowrate; flowing gaseous nitrogen-containing dopingmolecules into the reaction chamber; and forming a gas plasma in thereaction chamber.
 2. A method as in claim 1, further characterized inthat the organosilane molecules comprise molecules having no Si—H bonds.3. A method as in claim 2, further characterized in that theorganosilane molecules comprise tetramethyl silane.
 4. A method as inclaim 1, further characterized in that the doping molecules are selectedfrom the group consisting of nitrogen gas, N₂, and ammonia gas, NH₃. 5.A method as in claim 4, further characterized in that the step offlowing doping molecules into the reaction chamber comprises flowingdoping molecules at a doping flowrate more than four times greater thanthe organosilane flowrate.
 6. A method as in claim 1, further comprisinga step of: applying a low-frequency rf bias to the substrate.
 7. Amethod as in claim 6, further characterized in that the step of applyinga low-frequency rf bias to the substrate comprises applying a biashaving a frequency in a range of about from 100 kHz to 600 kHz.
 8. Amethod as in claim 6, further characterized in that the step of applyinga low-frequency rf bias to the substrate comprises applying a bias at apower in a range of about from 200 to 2000 Watts.
 9. A method as inclaim 6, further characterized in that the step of applying alow-frequency rf bias to the substrate comprises applying a bias at afrequency of about 250 kHz in a range of about from 300 to 600 Watts.10. A method as in claim 1, further characterized in that the step offorming a gas plasma comprises applying high-frequency rf power to thereaction chamber.
 11. A method as in claim 10, further characterized inthat the step of applying high-frequency rf power comprises applyingpower having a frequency in a range of about from 10 to 30 MHz.
 12. Amethod as in claim 10, further characterized in that the step ofapplying high-frequency rf power comprises applying power having afrequency of about 13.6 MHz.
 13. A method as in claim 10, furthercharacterized in that the step of applying high-frequency rf powercomprises applying power in a range of about from 200 to 4000 watts. 14.A method as in claim 10, further characterized in that the step ofapplying high-frequency rf power comprises applying power in a range ofabout from 300 to 1400 watts.
 15. A method as in claim 1, furthercomprising a step of: maintaining the reaction chamber at a pressure ina range of about from 0.8 to 10 Torr.
 16. A method as in claim 1,further comprising a step of: maintaining the reaction chamber at apressure in a range of about from 3 to 5 Torr.
 17. A method as in claim1, further comprising a step of: maintaining the reaction chamber at atemperature in a range of about from 200° to 600° C.
 18. A method as inclaim 1, further comprising a step of: maintaining the reaction chamberat a temperature in a range of about from 350° to 425° C.
 19. Anitrogen-doped silicon carbide film deposited in accordance with themethod of claim
 1. 20. An integrated circuit treated in accordance withthe method of claim
 1. 21. A plasma-enhanced method for depositingoxygen-doped silicon carbide on an integrated circuit substrate,comprising steps of: flowing gaseous organosilane molecules into areaction chamber at an organosilane flowrate; flowing gaseousoxygen-containing doping molecules into the reaction chamber; andforming a gas plasma in the reaction chamber.
 22. A method as in claim21, further characterized in that the organosilane molecules comprisemolecules having no Si—H bonds.
 23. A method as in claim 22, furthercharacterized in that the organosilane molecules comprise tetramethylsilane.
 24. A method as in claim 21, further characterized in that thedoping molecules comprise a weak oxidizer.
 25. A method as in claim 21,further characterized in that the doping molecules comprise carbondioxide, CO₂.
 26. A method as in claim 21, further characterized in thatthe step of flowing doping molecules into the reaction chamber comprisesflowing doping molecules at a doping flowrate more than four timesgreater than the organosilane flowrate.
 27. A method as in claim 21,further comprising a step of: applying a low-frequency rf bias to thesubstrate.
 28. A method as in claim 27, further characterized in thatthe step of applying a low-frequency rf bias to the substrate comprisesapplying a bias having a frequency in a range of about from 100 kHz to600 kHz.
 29. A method as in claim 27, further characterized in that thestep of applying a low-frequency rf bias to the substrate comprisesapplying a bias at a power in a range of about from 200 to 2000 Watts.30. A method as in claim 27, further characterized in that the step ofapplying a low-frequency rf bias to the substrate comprises applying abias at a frequency of about 250 kHz in a range of about from 400 to 800Watts.
 31. A method as in claim 21, further characterized in that thestep of forming a gas plasma comprises applying high-frequency rf powerto the reaction chamber.
 32. A method as in claim 31, furthercharacterized in that the step of applying high-frequency rf powercomprises applying power having a frequency in a range of about from 10to 30 MHz.
 33. A method as in claim 31, further characterized in thatthe step of applying high-frequency rf power comprises applying powerhaving a frequency of about 13.6 MHz.
 34. A method as in claim 31,further characterized in that the step of applying high-frequency rfpower comprises applying power in a range of about from 200 to 4000watts.
 35. A method as in claim 31, further characterized in that thestep of applying high-frequency rf power comprises applying power in arange of about from 300 to 1400 watts.
 36. A method as in claim 21,further comprising a step of: maintaining the reaction chamber at apressure in a range of about from 0.8 to 10 Torr.
 37. A method as inclaim 21, further comprising a step of: maintaining the reaction chamberat a pressure in a range of about from 1.5 to 3 Torr.
 38. A method as inclaim 21, further comprising a step of: maintaining the reaction chamberat a temperature in a range of about from 200° to 600° C.
 39. A methodas in claim 21, further comprising a step of: maintaining the reactionchamber at a temperature in a range of about from 350° to 425° C.
 40. Amethod as in claim 21, further characterized in that the oxygen dopingmolecules comprise a strong oxidizer.
 41. A method as in claim 40,further characterized in that the oxygen doping molecules are selectedfrom the group consisting of O₂, N₂O, and O₃.
 42. A method as in claim40, further characterized in that the step of flowing doping moleculesinto the reaction chamber comprises flowing oxygen molecules at a dopingflowrate about the same or less than the organosilane flowrate.
 43. Anoxygen-doped silicon carbide film deposited in accordance with themethod of claim
 31. 44. An integrated circuit treated in accordance withthe method of claim
 31. 45. A plasma-enhanced method for depositingdoped silicon carbide containing nitrogen dopant and oxygen dopant on anintegrated circuit substrate, comprising steps of: flowing gaseousorganosilane molecules into a reaction chamber at an organosilaneflowrate; flowing gaseous nitrogen doping molecules and oxygen dopingmolecules into the reaction chamber; and forming a gas plasma in thereaction chamber.
 46. A method as in claim 45, further characterized inthat the organosilane molecules comprise molecules having no Si—H bonds.47. A method as in claim 46, further characterized in that theorganosilane molecules comprise tetramethyl silane.
 48. A method as inclaim 45, further characterized in that the nitrogen doping moleculesare selected from the group consisting of nitrogen gas, N₂, and ammoniagas, NH₃.
 49. A method as in claim 45, further characterized in that theoxygen doping molecules comprise weak-oxidizer oxygen doping molecules.50. A method as in claim 49, further characterized in that theweak-oxidizer oxygen doping molecules comprise carbon dioxide, CO₂. 51.A method as in claim 50, further characterized in that the step offlowing doping molecules into the reaction chamber comprises flowingdoping molecules at a doping flowrate more than four times greater thanthe organosilane flowrate.
 52. A method as in claim 45, furthercharacterized in that the oxygen doping molecules comprisestrong-oxidizer oxygen doping molecules.
 53. A method as in claim 52,further characterized in that the strong-oxidizer oxygen dopingmolecules are selected from the group consisting of O₂, N₂O, and O₃. 54.A method as in claim 52, further characterized in that the step offlowing doping molecules into the reaction chamber comprises flowingnitrogen doping molecules at a nitrogen doping flowrate more than threetimes greater than the organosilane flowrate, and flowingstrong-oxidizer doping molecules at a strong-oxidizer doping flowrateabout the same or less than the organosilane flowrate.
 55. A method asin claim 45, further comprising a step of: applying a low-frequency rfbias to the substrate.
 56. A method as in claim 55, furthercharacterized in that the step of applying a low-frequency rf bias tothe substrate comprises applying a bias having a frequency in a range ofabout from 100 kHz to 600 kHz.
 57. A method as in claim 55, furthercharacterized in that the step of applying a low-frequency rf bias tothe substrate comprises applying a bias at a power in a range of aboutfrom 200 to 2000 Watts.
 58. A method as in claim 55, furthercharacterized in that the step of applying a low-frequency rf bias tothe substrate comprises applying a bias at a frequency of about 250 kHzin a range of about from 300 to 600 Watts.
 59. A method as in claim 45,further characterized in that the step of forming a gas plasma comprisesapplying high-frequency rf power to the reaction chamber.
 60. A methodas in claim 59, further characterized in that the step of applyinghigh-frequency rf power comprises applying power having a frequency in arange of about from 10 to 30 MHz.
 61. A method as in claim 59, furthercharacterized in that the step of applying high-frequency rf powercomprises applying power having a frequency of about 13.6 MHz.
 62. Amethod as in claim 59, further characterized in that the step ofapplying high-frequency rf power comprises applying power in a range ofabout from 200 to 4000 watts.
 63. A method as in claim 59, furthercharacterized in that the step of applying high-frequency rf powercomprises applying power in a range of about from 300 to 1400 watts. 64.A method as in claim 45, further comprising a step of: maintaining thereaction chamber at a pressure in a range of about from 0.8 to 10 Torr.65. A method as in claim 45, further comprising a step of: maintainingthe reaction chamber at a pressure in a range of about from 2 to 4 Torr.66. A method as in claim 45, further comprising a step of: maintainingthe reaction chamber at a temperature in a range of about from 200° to600° C.
 67. A method as in claim 45, further comprising a step of:maintaining the reaction chamber at a temperature in a range of aboutfrom 350° to 425° C.
 68. A silicon carbide film containing nitrogendopant and oxygen dopant deposited in accordance with the method ofclaim
 45. 69. An integrated circuit treated in accordance with themethod of claim 45.